This invention relates to drive systems for a vehicle, and more particularly, to auxiliary front wheel drive system for a vehicle.
In general, in drive systems for a vehicle wherein auxiliary front-wheel drive is provided, means are included for selectively supplying pressurized fluid to fluid motors for driving front wheels of the vehicle. The fluid driving such motors then exits from the motors through exhaust conduit means, and thence to tank. In general, when the front-wheel system is not in use, no pressurized fluid is being supplied to such motors, but the exhaust conduits are still in communication with tank so that the motors may have a tendency to rotate or "motor" during operation of only the rear-wheel drive of the vehicle. Further, it would be desirable to have the transmission of the vehicle operatively associated with the auxillary front-wheel drive, such that the shifting of the transmission regulates the pressurized fluid provided to the fluid motors.
Additionally, it will be understood that it is highly desirable to provide proper torque characteristics of the front wheel drive system in relation to the rear wheel drive system when both are in use.